Noncircumferential myofiber function: Impact on early diastolic filling inchildren

Circumferential and noncircumferential myofiber contraction may have varyin g impact on systolic and diastolic function. The purpose of this study was to determine the relation of circumferential, longitudinal, and oblique fib er shortening to early diastolic filling in children. Twenty-five patients (8.1 +/- 5.6 years of age; 12 boys and 13 girls) with normal echocardiogram s and no heart disease had prospective echocardiographic evaluation of circ umferential (shortening fraction, fractional area change), longitudinal (le ft ventricular axial shortening), combined circumferential and longitudinal (left ventricular ejection fraction), oblique (left ventricular systolic t wist [LVST]) shortening, and early diastolic filling. Mean LVST was 16 +/- 8 degrees. There was no relation between early diastolic filling indexes an d indexes of circumferential or longitudinal shortening. However, there was a significant inverse relation between heart rate-corrected E-wave acceler ation time and LVST (r = 0.63, P < .001). Oblique fiber shortening affects early diastolic filling in children. Describing the functional role of nonc ircumferential left ventricular myofibers may improve our understanding of global left ventricular function.